ahh gotcha... makes sense now. Yes, they do make an 11" rear as that is stock for the TRX700XX, but a very popular mod is to put Rancher hubs (I think) on them to get a 4x110 bolt pattern instead of the stock 4x144.
I don't know how easy it is for you to sit on a bunch of different quads and see which one you like the feel the best... I personally like the look of the lower bend bars (CR high) with a taller stem.
Welcome... for racing, you'll need nerf bars, tether, and ditch those heavy cast wheels.
There are tons of things that will be recommended, but I would definitely start with suspension.
That being said, it will all depend on your budget on which way to go.
welcome to the HQ... are you an employee of Monster or just a big fan?
if you're an employee send a couple cases of the OG green stuff and a couple cases of that new red one like you have sitting on your seat my way!
The great helmet debate has always intrigued me... we will spend thousands of dollars on our bikes & gear for cosmetics, but people always cheap out on helmets... how much is your brain worth to you?
If you are going to do a motor build, why not a 377... they don't make big numbers but you can twist the ever living piss out of them. We had one in a circle track car that lived at 8500 RPM for 2 full seasons running 2 different tracks. Definitely not an easy life, but a super fun motor.
Helmets are nothing to cheap out on or keep using to protect yourself a 2nd time... think about how much money we spend to keep our bikes looking, running, & rolling perfectly, and then take the cheap route on personal protection... how much is an intact skull worth?